During the company's recent annual meeting, Schultz shut down a shareholder (an anti-gay-marriage advocate, perhaps not coincidentally) who linked "disappointing" sales and earnings to the coffee chain's backing of Washington's Referendum 74, which legalized same-sex marriage in Starbucks' home state.

After defending Starbucks' financials to the loud applause of gathered delegates, Schultz told the dissenting shareholder, Tom Strobhar of the Corporate Morality Action Center: "You can sell your shares in Starbucks and buy shares in another company. Thank you very much."

Many of his fellow members of the Forbes 400 rich list have not just spoken out in support of same-sex marriage, but opened their considerable wallets at the state level, helping with November's equal rights victories. Others went a step further, founding their own super PACs (political action committees) during the last election cycle, providing infrastructure for their donations and fundraising.

The Seattle-based Amazon billionaire Jeff Bezos and his wife MacKenzie cut a check for $2.5 million to Washington United for Marriage, a group funding Referendum 74, the same cause Schultz's Starbucks backed. His donation helped secure a victory: same-sex marriage was legalized in November by a margin of 7.4%.

As the New York Times first reported, it was an email from a former Amazon employee from the company’s early days that prompted Bezos and his wife to publicly back equal rights. Jennifer Cast, a lesbian mother of four, sent Bezos a note last Sunday asking for $100,000 towards Referendum 74. She received a reply two days later confirming his support and $2.5 million donation.

As my colleague Ryan Mac has reported, Silicon Valley’s tech billionaires have been vocal equal rights supporters as far back as 2008 and California’s Proposition 8.

Billionaire media mogul David Geffen, who is openly gay, also backed the movement against Proposition 8 in 2008, giving $100,000 to the No On 8 campaign.

Other openly gay billionaires who’ve long backed the legalization of same-sex marriage include Jon Stryker, heir to the Stryker Corp. medical supply fortune. Stryker gave $602,000 in 2010 to the Gay & Lesbian Victory Fund.

Peter Thiel, the PayPal and Facebook billionaire, is also gay and has helped fund right-leaning LGBT group GOProud. In 2010, he hosted a GOProud event at his New York home that caused some consternation on the gay blogosphere for its host, Ann Coulter, who isn’t exactly known for her liberal views on marriage rights.

Perhaps the most prolific donor to the cause is not particularly well-known outside New York finance circles: hedge fund billionaire Paul Singer, who has given more than $10 million and counting.

Singer avoids the limelight more so than Bezos, but agreed to talk to the NYT’s Frank Bruni last year when he launched a pro-gay rights super PAC. The Republican billionaire pledged $1 million to start the group, and told Bruni his commitment stems from a cause close to home. He has a gay son, who married his partner in Massachusetts in 2o04.

Another billionaire backer of equal rights: Peter Lewis of insurance giant Progressive. Lewis himself is progressive in nature as well as name as the country’s highest-profile billionaire supporter of marijuana legalization. In an interview with Forbes in 2011, he revealed his main focus is drug reform, but the lifelong Democrat has donated to LGBT groups in the past. His son Jonathan is gay and a major Democratic fundraiser who gave $250,000 to the Gay & Lesbian Victory Fund in 2008.

Real estate developer and conservative political donor Steven Roth is another billionaire with a personal stake in the issue: like Lewis and Singer, he has a gay son. He and wife Daryl both gave $16,800 to support the campaigns of Republican New York state senators who backed same-sex marriage.

Fellow Republican donor and billionaire Steven Cohen also backed New York’s gay marriage initiative, as did Singer. Another notable super-rich supporter of the successful New York equal rights bid: the city’s billionaire Mayor Mike Bloomberg, a vocal LGBT advocate for years.

The next generation of Forbes 400 members is getting in on the act too. Laura Ricketts, daughter of conservative Chicago Cubs billionaire Joe, co-founded LPAC, a super PAC focused on lesbian rights. Ricketts -- the first openly lesbian owner of a major sports franchise -- helped LPAC raise and spend well over $500,000 on key races in the 2012 cycle. Their largest donation went to Wisconsin's Tammy Baldwin, who became the first openly gay U.S. Senator in history.

Who are we missing from our round-up of billionaire donors to equal rights? Email me: coconnor@forbes.com.